Which two signs should be interchanged to make the equation mathematically correct?
24 + 36 - 81 × 9 ÷ 2 = 42
Show answer & explanation
Correct answer: C
Explanation
The correct answer is Option 3 i.e. ÷ and ×.
Given equation: 24 + 36 - 81 × 9 ÷ 2 = 42
Option 1: ÷ and -
After interchanging the expression becomes:
= 24 + 36 ÷ 81 × 9 - 2 = 42
= 24 + 4 - 2
= 28 - 2
= 26 is not equal to 42.
Option 2: × and +
After interchanging the expression becomes:
= 24 × 36 - 81 + 9 ÷ 2 = 42
= 787.5 is not equal to 42.
Option 3: ÷ and ×
After interchanging the expression becomes:
= 24 + 36 - 81 ÷ 9 × 2 = 42
= 24 + 36 - 9 × 2
= 60 - 18
= 42 is equal to 42.
As we have found our answer, there is no need to check further options.
Hence, ÷ and × is the correct answer.